Why Is It So Cold In Here? Setting The Office Thermostat Right - For Both Genders

If you work in an office, chances are you or the person sitting next to you has grumbled about it being too hot or cold. No one likes rugging up on a summer’s day to contend with the air-conditioning. Or having to shed one too many layers in winter to compensate for stifling heat indoors.

According to a paper published in the journal Nature Climate Change, this scenario is more likely if you’re a woman. Climate control systems in office buildings are often set according to an old formula based on men’s thermal comfort. This gender bias, the authors argue, is wasting energy.

Cold office worker picture from Shutterstock

What is thermal comfort?

Keeping office workers from feeling too hot or too cold is no simple task. While most office air conditioners control only air temperature, the way we exchange heat with the environment depends on a suite of environmental factors. And so does our thermal comfort.

Engineers need to consider:

  • the humidity
  • the movement of air (wind speed)
  • the radiation temperature (the temperature of everything the body can “see”)
  • the temperature of everything we touch.

In the 1970s, Danish engineer Ole Fanger developed a model to determine the combination of environmental variables that we find comfortable.

Because heat exchange also depends on individual factors such as body size (and therefore body surface area), metabolic rate (that determines metabolic heat production), tissue insulation (related to the amount of body fat), and clothing, Fanger’s own experiments showed that no office thermal environment ever would satisfy everyone.

Even before Fanger, we knew that, at the low wind speeds typical of offices, radiant heat exchange mattered more than convective heat exchange. In other words, radiation temperature is more important for thermal comfort than air temperature. You could argue that offices should have wall conditioners, rather than air conditioners.

In their Nature Climate Change paper, Dutch researchers Boris Kingma and Wouter van Marken Lichtenbelt show that if the thermostat is set for men, as it usually is, the air temperature will be too low for women.

Because women are smaller, the authors explain, they generate less metabolic heat than men, and so will not feel comfortable in winter at office temperatures set for men.

By the same logic, if the thermostat is set for Europeans, it will be too low for Asians, who weigh, on average, 30% less than Europeans.

In countries such as Australia and South Africa, where air conditioning generally is used for cooling, setting the thermostat to satisfy large people in summer will leave smaller people feeling too cold.

But while Fanger’s equations predict thermal comfort – how satisfied we are with the thermal environment – that is only one of the body functions relevant to the question of where we set the thermostat.

More than just comfort

Heat exchange also affects our body temperature control (how hot our bodies are), thermal sensation (how hot or cold we feel the environment to be), and our performance (how well we do on a particular task).

Those body functions are not necessarily correlated. In a hot bath, for instance, body temperature rises and we feel hot, but we meet Fanger’s criterion for thermal comfort: we wouldn’t want the temperature to be any different.

We perform some cognitive and physical tasks best when we’re slightly-uncomfortably cold. But manual dexterity is better at a warm 32°C than at 20°C in simulated factory work.

Performance at some tasks drops off when body temperature rises, even if we do not feel the environment as warm. For that reason, and those outlined in the Nature Climate Change paper, children probably underperform on learning tasks in classrooms that teachers assess as feeling just right. Perhaps the smaller children should set the thermostat.

As if all that complexity weren’t enough, Australian researchers have challenged Fanger’s 1970s thermal comfort model on the basis of the concept of adaptive thermal comfort. Should we set the thermostat at the same level in winter, they asked, when we are acclimated to colder outdoor environments, as in summer?

Some occupants of offices in the tropics want the thermostat set higher than Fanger predicts. Thirty years ago, people of European ancestry living in Darwin rejected air conditioning in the “the Dry” (July and August) because they felt overcooled. Though it’s unclear whether modern Darwinians, many of whom use air-conditioning at home, would say the same.

So, what can we do?

We certainly could maintain thermal comfort and simultaneously relax the demands on the thermostat if we were prepared to wear warmer clothes in our offices in winter and cooler clothes in summer. Selecting clothing also would solve the dilemma of providing thermal comfort to both men and women in the same office.

In the new Nature Climate Change paper, the authors estimate that energy consumption of residences and offices “adds up to about 30% of total carbon dioxide emissions”.

It’s true, we could substantially reduce the energy required for acceptable thermal environments in offices and consequently reduce greenhouse gases. But that approach would require us to abandon the compulsion to create a shirt-sleeve thermal environment in offices, and to vary the thermostat between summer and winter.

We would also need to switch to wall-conditioning rather than air-conditioning and use green engineering to get the thermal design of the office building right. We can be comfortable without it costing the earth.

<a href="http://theconversation.com/profiles/shane-maloney-152858">Shane Maloney, Professor and Head of School, Anatomy Physiology and Human Biology, University of Western Australia; Andrea Fuller, Professor, School of Physiology; Director, Brain Function Research Group, University of the Witwatersrand, and Duncan Mitchell, Honorary Professorial Research Fellow at the University of the Witwatersrand, Johannesburg; Adjunct Professor in the School of Anatomy, Physiology and Human Biology, University of Western Australia

This article was originally published on The Conversation.


    You want to discuss gender bias? Consider office men are expected to wear suits in the summer, while female employees can get away with skirts and lose fitting blouses... This is about men having a STRICTER DRESS CODE than their equivalent female employees, therefore have to compensate by lowering the thermostat. It's not hard to put on a cardigan... it is hard to keep sweat off your expensive suit when it gets too hot. If you really think females are the victim in this scenario you are merely showing your cognitive bias.

      It is a very generalised statement you are making. The ladies at the office I work for are always rugged up but still complain it is cold.

        It's not any more generalised than the statements made by the writers of the paper.

          The arguments portrayed by this article are backed with evidence from scientific papers.

          The standard basis for a person doing light office work is 150W. This is based on past evidence, which according to the articles, is based on men.

          A women will generally have a lower metabolic rate than men, their heat output will be around 110W. Meaning the design of the A/C system is over sized for their requirements.

          When a system is over sized, there is an issue of 'over-cooling' where the system can't adjust the fan / compressor speed in the time frame and the room temperature falls below the dead band.

          Last edited 25/09/15 1:42 pm

            It is a lot easier to warm yourself by putting on another layer, than it is to cool yourself when you cannot remove another. These people need to learn how to deal with their own problems instead of forcing the world to bend to their will.

      Where are you working that makes you keep your suit jacket on inside, at your desk? Sounds like the sort of place that means that the ladies you work with are expected to be wearing stockings under their skirts and probably heels.

      You're right. We should start by relaxing corporate dress culture. It's designed for cold European climates where layers and wool are a sensible choice, and doesn't make sense for the majority of Australia.

        I actually wear high visibility, cotton drill work wear just like the females I work with. Nobody complains about the cold because we're all wearing the same stuff.

        Articles like this/studies like this start out with a bias, saying that the women are being unfairly treated; their study then confirms their bias and they go "oh look how bad the woman have it." They don't realise their study is flawed; they don't look at it with a purely objective lens to see the real cause of the issue.

        You're correct in saying that less strict dress codes for male workers would reduce the problem's frequency.

    It's not hard to put on a sweater if it's cold, but there's only so many layers I can remove due to heat

    A scientific paper that has ignored some very basic facts of human physiology, which is surprising given it is written by two people from the Department of Nutrition.

    1) Men tend to have more body fat on them
    2) Men tend to have a more stable body temperature
    3) Men tend to eat more than women
    4) Men tend to have higher iron content in their blood
    5) Men tend to have better immune systems

    All of those factors mean that men, in general, will have a fairly constant (and higher) body temperature, though naturally extremes of body type may feel the temperature differently - A chap of 120kg may prefer a cooler temperature than his colleague of 85kg.
    As humans, we tend to base our actions and methodologies on the rule of averages, not individual data points, which why the Number 17 bus does not stop at your house but at the bus stop 300m away, or why Chicken Parmigiana is on the menu at almost every RSL in the country.

    If the majority of the office is occupied by women, then it makes sense to turn the temperature to one that suits the majority. It's what more moderate types call 'the law of averages', but if you want to make it sound edgy, calling it 'gender bias' get more discussion.

    The most surprising fact that was ignored, is that women have periods, and during this time, will often feel the cold more keenly, because their iron content is lower and because it is a natural low point in the bodys cycle - often this is when a woman will contract a cold or have a harder time fighting one off, because her immune system is doing double duty.
    So if you've ever wondered why your missus never seems to shake that cough, it's because just as the body is about to defeat the cold, and hello, the period comes along and ruins everything.

    Their study seems to be mostly concerned with young female office workers, and does not discuss the metabolic rate of more mature women

    Based on that, it is only natural to base the temperature on the average temperature, and from my experiences in offices, most people are fairly accepting if you put on an extra layer of clothing, but tend to take a dim view if you're so hot you have to strip down to your boxers.

    About the only thing worth mentioning from it, is this: "Indoor climate regulations are based on an empirical thermal comfort model that was developed in the 1960s"
    Assuming that Australia followed those calculations, we should probably reassess those calculations, because both climate and body type have changed significantly since then.

    Last edited 25/09/15 2:47 pm

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